Fig. 1

Exogenous ABA priming upregulated the transcriptional expression levels of ABA-responsive genes in rice grains under heat stress. The rice plants were sprayed with distilled water, 50 μM ABA or 10 μM fluridone (FLU) at the 5th d after initial heading stage (AIH) or 12th d after initial heading stage, and then subjected to unstressed or heat stress conditions at 8–14 days after initial heading (AIH) stage or 15–21 days after initial heading stage, respectively. Rice grains at the indicated treatment times of 0 d, 3 d, 5 d and 7 d were sampled in liquid nitrogen which were used to measure the expression levels of relative genes. Relative expression levels of ABA-responsive genes, SalT (A, B) and OsWsi18 (C, D) were measured at the indicated treatment days. A quantitative real-time polymerase chain reaction was performed using OsACT1 as an internal standard. The expression levels of the untreated control (CK) at 0 d were set as the unit to calculate the expression levels. Values are means ± SDs, n = 3. Different letters on the column represent significant differences (P < 0.05) between different treatments based on Duncan’s test